.auto-loan-calculator-wrapper {
font-family: 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
max-width: 800px;
margin: 0 auto;
color: #333;
line-height: 1.6;
}
.alc-container {
background-color: #ffffff;
border: 1px solid #e0e0e0;
border-radius: 12px;
box-shadow: 0 4px 12px rgba(0,0,0,0.05);
padding: 30px;
margin-bottom: 40px;
}
.alc-grid {
display: grid;
grid-template-columns: 1fr 1fr;
gap: 20px;
}
@media (max-width: 600px) {
.alc-grid { grid-template-columns: 1fr; }
}
.alc-input-group {
margin-bottom: 15px;
}
.alc-input-group label {
display: block;
font-weight: 600;
margin-bottom: 8px;
color: #2c3e50;
}
.alc-input-group input {
width: 100%;
padding: 12px;
border: 1px solid #ccc;
border-radius: 6px;
font-size: 16px;
box-sizing: border-box;
transition: border-color 0.3s;
}
.alc-input-group input:focus {
border-color: #3498db;
outline: none;
}
.alc-btn-container {
grid-column: 1 / -1;
text-align: center;
margin-top: 10px;
}
.alc-btn {
background-color: #2980b9;
color: white;
border: none;
padding: 14px 40px;
font-size: 18px;
font-weight: bold;
border-radius: 6px;
cursor: pointer;
transition: background-color 0.3s;
}
.alc-btn:hover {
background-color: #1a5c85;
}
.alc-results {
background-color: #f8f9fa;
border-radius: 8px;
padding: 25px;
margin-top: 30px;
border-left: 5px solid #2980b9;
}
.alc-result-row {
display: flex;
justify-content: space-between;
margin-bottom: 15px;
border-bottom: 1px solid #e9ecef;
padding-bottom: 10px;
}
.alc-result-row:last-child {
border-bottom: none;
margin-bottom: 0;
padding-bottom: 0;
}
.alc-result-label {
color: #666;
font-weight: 500;
}
.alc-result-value {
font-weight: 700;
font-size: 18px;
color: #2c3e50;
}
.alc-highlight {
color: #27ae60;
font-size: 24px;
}
.alc-article {
margin-top: 50px;
}
.alc-article h2 {
color: #2c3e50;
border-bottom: 2px solid #3498db;
padding-bottom: 10px;
margin-top: 40px;
}
.alc-article h3 {
color: #34495e;
margin-top: 25px;
}
.alc-article p, .alc-article li {
color: #555;
font-size: 17px;
}
function calculateCarLoan() {
// Get Input Values
var price = parseFloat(document.getElementById("vehiclePrice").value);
var taxRate = parseFloat(document.getElementById("salesTax").value);
var down = parseFloat(document.getElementById("downPayment").value);
var trade = parseFloat(document.getElementById("tradeInValue").value);
var rate = parseFloat(document.getElementById("interestRate").value);
var months = parseFloat(document.getElementById("loanTerm").value);
// Sanitize inputs
if (isNaN(price)) price = 0;
if (isNaN(taxRate)) taxRate = 0;
if (isNaN(down)) down = 0;
if (isNaN(trade)) trade = 0;
if (isNaN(rate)) rate = 0;
if (isNaN(months) || months === 0) months = 60; // Default to 60 if empty
// Calculate Tax (Tax is usually applied to the price before trade-in in many jurisdictions,
// though some allow tax credits on trade-ins. We will use the conservative approach: Tax on full price).
var taxAmount = price * (taxRate / 100);
// Calculate Amount to Finance
// Formula: (Price + Tax) – Down Payment – Trade In
var totalUpfront = price + taxAmount;
var loanPrincipal = totalUpfront – down – trade;
var monthlyPayment = 0;
var totalInterest = 0;
var totalCost = 0;
if (loanPrincipal <= 0) {
// No loan needed
monthlyPayment = 0;
totalInterest = 0;
loanPrincipal = 0;
totalCost = price + taxAmount;
} else {
if (rate === 0) {
// 0% APR case
monthlyPayment = loanPrincipal / months;
totalInterest = 0;
} else {
// Standard Amortization Formula
// M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1 ]
var i = (rate / 100) / 12; // Monthly interest rate
var factor = Math.pow(1 + i, months);
monthlyPayment = loanPrincipal * ((i * factor) / (factor – 1));
totalInterest = (monthlyPayment * months) – loanPrincipal;
}
totalCost = (price + taxAmount) + totalInterest;
}
// Update UI
document.getElementById("monthlyPaymentResult").innerHTML = "$" + monthlyPayment.toFixed(2);
document.getElementById("loanAmountResult").innerHTML = "$" + loanPrincipal.toFixed(2);
document.getElementById("taxAmountResult").innerHTML = "$" + taxAmount.toFixed(2);
document.getElementById("totalInterestResult").innerHTML = "$" + totalInterest.toFixed(2);
document.getElementById("totalCostResult").innerHTML = "$" + totalCost.toFixed(2);
// Show results
document.getElementById("resultsSection").style.display = "block";
}
Auto Loan Calculator
Estimated Monthly Payment:
–
Total Loan Amount (financed):
–
Sales Tax Amount:
–
Total Interest Paid:
–
Total Cost of Car:
–
Understanding Your Auto Loan Options
Purchasing a vehicle is one of the most significant financial decisions many households make, second only to buying a home. Using this Auto Loan Calculator allows you to estimate your monthly payments accurately by factoring in sales tax, trade-in values, and varying interest rates.
How the Calculator Works
This tool uses the standard amortization formula used by banks and credit unions. Here is a breakdown of the key inputs required to get an accurate estimate:
- Vehicle Price: The sticker price of the car you intend to buy, negotiated before tax and fees.
- Sales Tax: State and local taxes can add significantly to the total cost. This calculator adds tax to the vehicle price to ensure you aren't surprised by the final "out-the-door" price.
- Trade-In & Down Payment: Equity from your current vehicle or cash upfront reduces the principal loan amount, which lowers both your monthly payment and the total interest paid over the life of the loan.
- APR (Annual Percentage Rate): Your credit score largely determines this rate. Even a 1% difference can save or cost you hundreds of dollars.
- Loan Term: Common terms are 36, 48, 60, 72, or 84 months. While longer terms lower your monthly bill, they significantly increase the total interest paid.
The Impact of Loan Terms on Total Interest
Many buyers focus solely on the monthly payment, opting for 72 or 84-month loans to make expensive cars "affordable." However, this strategy often leads to negative equity (being "underwater" on the loan) because the car depreciates faster than you pay off the principal.
Example Scenario
Imagine financing $30,000 at 6% interest:
- 60-month term: Monthly payment is approx. $580. Total interest paid: ~$4,800.
- 84-month term: Monthly payment drops to approx. $438. Total interest paid: ~$6,800.
By extending the loan by two years, you save $142 a month but pay $2,000 more in interest.
Tips for Getting the Best Rate
Before heading to the dealership, check your credit score and consider getting pre-approved by a credit union or bank. Dealership financing is convenient but often comes with a markup on the interest rate. Having a pre-approval letter gives you leverage to negotiate a better deal on the car price and the financing terms.